1. Field of the Invention
The present invention relates to a passenger seat for use in a motor vehicle, and more particularly to a passenger seat suitable for use as a front seat in a motor vehicle.
2. Description of the Relevant Art
Generally, conventional passenger seats for motor vehicles such as automobiles have a plurality of springs extending between confronting members of a seat frame and a cushioning pad disposed on the springs. Motor vehicle passenger seats are required to have a sufficient degree of rigidity to withstand inertial forces applied when the motor vehicle starts to move or in other occasions in which the motor vehicle is subject to acceleration. Front passenger seats are also required to provide a space between the lower surface of the rear portion of the seat cushion and the motor vehicle floor, which space is wide enough for rear seat passengers to put their feet therein.
To meet the above requirements, Japanese Laid-Open Utility Model Publication No. 63-77547 discloses a front passenger seat designed for allowing a rear seat passenger to insert the feet below the front passenger seat, the front passenger seat retaining a desired level of rigidity. The front passenger seat includes a seat frame having a substantially U-shaped opening defined centrally in a rear portion thereof and two superposed panels joined to the seat frame and providing in a front portion of the seat frame a plurality of transverse reinforcing members of closed hollow cross section. The front passenger seat also has a pair of beams of closed hollow cross section disposed on lateral sides, respectively, of the seat frame and extending rearwardly.
With the disclosed passenger seat, the U-shaped opening defined in the rear central portion of the seat frame tends to create a gap between the lower end of the seat back and the rear end of the seat cushion, and also is liable to permit the rear central portion of the seat to flex down when a passenger is seated on the seat. In the disclosed passenger seat, a plate is supported on the seat frame by coil springs, and a cushioning pad is mounted on the plate. Therefore, the passenger seat may not have a proper body pressure distribution when a passenger of a different body profile is seated. The plate may be replaced with a plurality of zigzag springs. However, the rear ends of some of the zigzag springs could not be supported on the seat frame because of the opening defined in the rear central portion of the seat frame.